This invention relates to an apparatus including a regenerative burner for repetitively regenerating a trip element located in the exhaust system of an internal combustion engine.
It has been proposed to purify exhaust gas from an automobile internal combustion engine by employing a trap or particle filter element located in the exhaust system of the engine to collect therein carbon or other particles included in the exhaust gas discharged from the engine. The trap element should be repetitively regenerated each time a regeneration requirement occurs; that is, when the amount of the exhaust particles collected in the trap element reaches a limit value. For this purpose, a regenerative burner is disposed in the exhaust system upstream of the trap element, the regenerative burner including a glow plug operable to ignite and burn an air-fuel mixture supplied into the burner so as to burn the exhaust particles collected in the trap element when a regeneration requirement occurs.
The regenerative burner has a liner closed at its upstream end by an end plate to define therein a combustion chamber opening toward the trap element. The liner has a peripheral wall formed with holes or slits to permit flow of exhaust gas from the engine exhaust conduit to the trap element. A cup-shaped member is disposed within the combustion chamber to define therein an evaporation chamber which has an adequate supply of air-fuel mixture. The cup-shaped member has a peripheral wall formed with holes or slits to permit fuel droplets to fall onto the glow plug located below the cup-shaped member within the combustion chamber. The glow plug is actuated to ignite fuel droplets falling thereon to ignite the air-fuel mixture blown off into the combustion chamber when a regeneration requirement occurs.
A disadvantages with such an apparatus is that the flow of air-fuel mixture from the evaporation chamber into the combustion chamber causes fluid flow to cool down the glow plug and deviate the falling fuel droplets away from the glow plug. The result is a degraded ability to ignite the air-fuel mixture.
Therefore, the present invention provides an exhaust purification apparatus including an improved regenerative burner which can provide a higher ability to ignite air-fuel mixture supplied therein.